Abstract: Preferred embodiments of a freestanding, heat resistant microporous polymer film (10) constructed for use in an energy storage device (70, 100) implements one or more of the following approaches to exhibit excellent high temperature mechanical and dimensional stability: incorporation into a porous polyolefin film of sufficiently high loading levels of inorganic or ceramic filler material (16) to maintain porosity (18) and achieve low thermal shrinkage; use of crosslinkable polyethylene to contribute to crosslinking the polymer matrix (14) in a highly inorganic material-filled polyolefin film; and heat treating or annealing of biaxially oriented, highly inorganic material-filled polyolefin film above the melting point temperature of the polymer matrix to reduce residual stress while maintaining high porosity. The freestanding, heat resistant microporous polymer film embodiments exhibit extremely low resistance, as evidenced by MacMullin numbers of less than 4.5.

Abstract: Redundant joints for a wide variety of redundant-joint structures have three-way plumbing elbows (1, 5, 6) with coupling sleeves (2) into which two-way plumbing elbows (9, 13, 14) are inserted and rotated to form an infinite variety of angles of joining edges or sides of structural assemblies bordered by cylindrical beams (15) inserted into sleeves (12) in the two-way elbows. The three-way elbows can have different angles for particular structures than employed for conventional plumbing uses. For other structures, the three-way elbows have the same or similar angles as those employed for conventional plumbing. Two-way elbows with a coupling sleeve at one end and a pipe-sized opposite extension employed for particular forms also can have different or the same angles as employed for conventional plumbing.